Personally I went with the Garmin Edge 305. I really like it. Wireless, supports HR, speed, and cadnece, can calculate speed based on GPS data or a magnet attached to the wheel (on an indoor trainer it still works fine, outside you can turn on the GPS and get speed that way), allows you to enter waypoints / create routes, and a lot more.

The display can show you up to 16 different data fields on two screens (8 maximum fields per screen), or as little as one field per screen (total of two). After your ride you can use the included software to connect the GPS to your PC and download all the ride data. Then you can see all sorts of cool charts and graphs and whatnot.

Both the Polar and Cateye were cheaper, but they did not have the GPS functions nor the cool included software.

Personally I went with the Garmin Edge 305. I really like it. Wireless, supports HR, speed, and cadnece, can calculate speed based on GPS data or a magnet attached to the wheel (on an indoor trainer it still works fine, outside you can turn on the GPS and get speed that way), allows you to enter waypoints / create routes, and a lot more.

The display can show you up to 16 different data fields on two screens (8 maximum fields per screen), or as little as one field per screen (total of two). After your ride you can use the included software to connect the GPS to your PC and download all the ride data. Then you can see all sorts of cool charts and graphs and whatnot.

Both the Polar and Cateye were cheaper, but they did not have the GPS functions nor the cool included software.